SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '433460453f407607f4934e3c74ed48d507684c12c463112908997bedbc849a56' 
  AND token = 'TpcghNbyuOI8C77zM1NUY1FwNiJfXmF0gfVRrrAmoVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}